In the present work, new matrix bead formulations based on linear and branched polysaccharides have been developed using an ionic gelation technique, and their potential use as oral drug carriers has been evaluated. Using calcium chloride as a cross-linking agent and sodium diclofenac (SD), as a model drug, acacia gum-calcium alginate matrix beads were formulated.The response surface methodology based on 3 2 factorial design was used as a statistical method to evaluate and optimize the effects of the biopolymers-blend ratio and the concentration of calcium chloride on the particle size (mm), density (g/cm 3 ), drug encapsulation efficiency (%), and the cumulative drug release after 8 hours (R 8h ,%). The optimized beads with the highest drug encapsulation efficiency were examined for a drug-excipients compatibility by powder X-ray diffraction, differential scanning calorimetry, thermo-gravimetric analysis, and Fourier transforminfrared spectroscopy analyses. The swelling and degradation of the matrix beads were found to be influenced by the pH of medium. Higher degrees of swelling were observed in intestinal pH than in stomach pH. Accordingly, the drug release study showed that the amount of SD released from the acacia gum-calcium alginate beads was higher in intestinal pH than in stomach pH. Therefore, the in vitro drug release from the SD-loaded beads appears to follow the controlledrelease (Hixson-Crowell) pattern involving a case-2 transport mechanism operated by swelling and relaxation of the polymeric blend matrix. KEYWORDS acacia gum-calcium alginate, beads, branched polysaccharide, linear polysaccharide, oral drug delivery 1 | INTRODUCTION Polysaccharides represent a class of natural chemical compounds characterized by repetitive structural units with a wide degree of dispersion. 1 A growing interest in these chemical compounds has resulted in the identification of a number of important biochemical and biomedical applications, not only because of their low cost, biocompatibility, biodegradability, high swelling capability, and stability in various pHs but also because of their potential use in controlled drug delivery systems. 1-4 Different forms of natural polysaccharides such as nanostructures, 5,6 films, 7 tablets, 8,9 and hydrogels 10 have been reported in the literature. Recently, attention has been focused on the development of ionic polysaccharide hydrogel beads for use as oral drug carriers. 11 Different ionic polysaccharide beads based on sodium alginate (SA), 12 chitosan, 13 and pectin 14 have been extensively developed and examined for the encapsulation of a wide range of drugs. 15,16 However, major limitations of these ionic beads are the small drug encapsulation capacity due to drug leaching through the pores and the fast degradation in alkaline pH media resulting in burst release of drugs. 17 To overcome the limitations of these ionic polysaccharide beads, the combination of ionic and natural polysaccharides has been proposed. 18,19 Most of the reported results using this approach are based ...

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Abstract:The miscibility behavior of poly(styrene-co-cinnamic acid) (PSCA) with poly(methyl methacrylate) (PMMA), poly[(methyl methacrylate)-co-(4-vinylpyridine)] (PMMA4VP) and poly[(methyl methacrylate)-co-(2-vinylpyridine)] (PMMA2VP) was studied. DSC measurements indicated that PSCA23 containing 23 mol% of carboxylic acid units was miscible with PMMA, PMMA2VP and PMMA4VP as established from the observation of a single composition dependent glass transition temperature. Miscibility was induced via hydrogen bonding as evidenced by IR frequency shifts of the hydroxyl stretching vibrations of the acid copolymer in the blends. Interpolymer hydrogen bonding formation within the binary systems was also investigated by viscosimetric study of dilute solutions in toluene. For PMMA/PSCA5 blends the viscosity of the mixtures was close to the weight average viscosities of the individual polymer while for blend solutions of PSCA5 with PMMA2VP and PMMA4VP, the interactions were sufficiently strong to form interpolymer complexes with a decrease in viscosity in comparison to the additivity rule.

In this study we report on the preparation and characterization of biocomposites based on a sodium montmorillonite-ibuprofen (MtIb) hybrid and neat poly(ethylene glycol), neat sodium carboxymethylcellulose or poly(ethylene glycol)-carboxymethylcellulose blend 50/50 biocomposites as drug carriers. Ib, a poorly soluble drug, was first intercalated into sodium Mt and then the resulting hybrid was compounded with the different polymeric matrices. Ib incorporation efficiency in Mt was determined by UV-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction and thermal analysis. Both X-ray diffraction and differential scanning calorimetric studies revealed that the intercalation of Ib between the clay layers induced amorphization of the drug. Differential scanning calorimetry and Fourier transform infrared spectroscopy revealed the development of strong interactions between Ib and the polymer matrix. A study of the release of Ib from the synthesized biocomposites in simulated intestinal fluid (pH 7.4) was investigated. To better understand the release mechanism of drug molecules from the different carriers, several kinetic models have been applied.

SUMMARY: Compatibilization of an immiscible polymer pair, polystyrene and poly(ethyl methacrylate), is achieved by introducing along the polymer chains cinnamic acid and 2-dimethylaminoethyl methacrylate groups, respectively. The miscibility behavior of a series of poly[styrene-co-(cinnamic acid)] (PSCA) copolymers containing 5, 8, and 23 mol-% of acidic units, with poly[(ethyl methacrylate)-co-(2-dimethylaminoethyl methacrylate)] (PEMADAE) was investigated by DSC and FTIR. Based on the single composition-dependent glass transition criterion, each PSCA copolymer is miscible with PEMADAE over the three blend compositions studied. The glass transition temperatures are higher than predicted according to the additivity principle. This indicates the occurrence of strong intermolecular interactions between the polymeric chains of the two components. The T g -composition curves of the investigated systems are interpreted according to the Kwei and the Schneider approaches. The results of the FTIR study reveal that the changes detected in the carbonyl stretching frequency region are the consequence of hydrogen bonding between the carboxylic acid groups in PSCA and the carbonyl groups in PEMADAE.